1,721,109 research outputs found
Dataset for the figures in 'Reducing railway-induced ground-borne vibration by using open trenches and soft-filled barriers'
No full textData for the figures in the paper by Thompson, D., Jiang, J., Toward, M.G.R, Hussein, M.F.M., Ntotsios, E., Dickmans, A., Coulier, P., Lombaert, G. and Degrande, G. (2016) Reducing railway-induced ground-borne vibration by using open trenches and soft-filled barriers. Soil Dynamics and Earthquake Engineering</span
A two-step procedure for damage detection in beam structures with incomplete mode shapes
Full text linkIn this work, we present a two-step procedure for damage identification in beam structures exploiting modal curvature changes. The reconstruction of modal curvatures requires the knowledge of several mode shape components along the analyzed beam. This requirement is practically unachievable when mode shapes are identified via vibration-based monitoring using a limited number of accelerometers. To overcome this limitation, in the first step of the proposed procedure, we perform a mode shape expansion employing a reduced subset of measured modal components. The remaining measured components are used as control parameters to formulate a first hypothesis on damage location and extent. For this purpose, the expansion procedure is performed considering a number of possible damage scenarios, consisting of a location and a severity (loss of stiffness) of the damage. Using the Total modal assurance criterion (TMAC), we select the expanded modes with the highest degree of correspondence with the measured control components. These expanded modes are thus associated with a first guess of the damage location and severity. In the next step, this initial damage identification is verified through the computation of a modal curvature-based damage index. If the curvature-based damage identification confirms the previous identification, the damage location and extent are determined. The procedure can be easily extended to identify multiple simultaneously damaged elements. The approach is numerically validated using a benchmark beam modeled via finite elements, investigating the influence of different parameters such as noise, position of the control components and beam discretization on the identification success rate. Finally, the procedure is tested on two experimental specimens: a steel beam, with three different damage configurations and a concrete beam progressively damaged with multiple damage locations
Value of information of static and modal data for a concrete bridge exposed to reinforcement corrosion
No full textMeasurements performed on ageing bridges can provide information on the remaining capacity of these structures. Nevertheless, these measurements come at a cost, whereas the budgets for maintenance are limited. Based on pre-posterior analyses, the Value of Information (VoI) of these measurements can be determined on beforehand and the most optimal measuring strategy can be chosen. However, applying these VoI analyses to real-world structures, considering the time-dependent and spatial character of degradation, can be challenging. In this work, a case study is considered where the VoI analysis is applied to a reinforced concrete girder bridge subjected to corrosion, considering two situations: one with corrosion due to carbonation and one with corrosion due to chlorides. The influence of different assumptions in the VoI analysis is investigated
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Pedestrian-Induced Vibrations of Footbridges: An Extended Spectral Approach
No full textsponsorship: The first author is a postdoctoral fellow of the Research Foundation Flanders (FWO, 12E0816N). The research presented in this paper was performed within the framework of a research stay at the University of Genoa (FWO, Travel Grant V404918N). The financial support is gratefully acknowledged. (12E0816N, V404918N)status: Publishe
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Mitigation of railway induced vibrations by using heavy masses next to the track
No full textThe effectiveness of heavy masses next to the track to reduce railway induced vibration is discussed.These heavy masses next to the track could be built as a gabion wall also used as noise barriers or as a concrete wall.Since the performance of mitigation measures on the transmission path is strongly determined by local groundconditions, a parametric study has been performed for a range of possible designs in a set of different ground types. A 2.5D coupled finite element - boundary element methodology was adopted, assuming that the geometry of the problem is invariant in the longitudinal direction along the track. It is found that the gabion walls start to be effective above a mass-spring resonance frequency which is determined by the mass of the gabion wall and the stiffness of the soil. A gabion wall will be more effective at sites with a soft soil. Increasing the mass will improve the insertion loss at lower frequencies. The effectiveness at higher frequencies is increased by making the footprint of the gabion walls as large and stiff as possible, and by placing the masses next to each other without any connection. For homogeneous soil conditions, the effectiveness is nearly independent of the distance behind the walls. When a softer top layer is present, the wave impeding effect is strongly decreased with increasing distance behind the walls.<br/
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